Ok so here is the situation hopefully u guys can shed some light,
the car is 92 318i with m42 engine

I went for my first e test last sat- failed bad Co% was 7.32 max is .036 I replaced the O2 sensor and brought me down to 1.37 still very high meaning running rich still right? What I have done is replaced plugs fuel filter and o2 sensor,I even tryed the menthol hydrate trick it brought my reading down abit on my hc suppose yto read I think 64 was 84 still not enough,Left the test place and threw another code for MAF...Im like wtf,Went to the scrap yard today picked one up from a 93 318is 1.8 code is still present but runs even worse smells very rich idle bounces all over the board at a light and almost stalls,Could this be a bad MAF too? Im stumped any help is greatly appreciated thank in advance.

mirek

02-05-2008 06:53 PM

you can pull the boot off the maf plug and using a multimeter check to see if it's sending a reading.

m3guy

02-05-2008 07:33 PM

hey

So If I check resistance and its sending,the maf is bad.....My other one threw a code but didn't affect really the way it drove sometimes jsut stall once this one is crazy and u can smell it running rich and its bucking thanks in advance bro

mirek

02-05-2008 07:37 PM

Well you check, and if it's not sending it's definately bad. The bentley manual will tell you what is at spec, and if it's sending within spec it's good.

Clean your old one, and put it back, the new one obviously sounds like it's bad.

m3guy

02-05-2008 07:45 PM

would a bad maf give me a bad reading on the etest,My co% is still stupidly high..and Hc is still up there I think limit is 67 Im at 110,My CO is at 1.67 its suppose to be 0.37

mirek

02-05-2008 08:01 PM

Have a shop do a sniff test before and after your cat.

A bad MAF can give you a bad emissions reading.

Mickey Knox

02-05-2008 09:30 PM

whatever you do

DO NOT MEASSURE RESISTANCE ON A OPERATING CIRCUIT.

the only thing you can measure on operating circuit is voltage

quick breakdown.

Resistance measuring - works by sending a small voltage and measuring the amperage inside the voltmeter.

Voltage measuring - works by measuring the amperage the voltage on the measuring tips causes inside the voltmeter

Amperage measuring - sets internal resistance to next to and needs to be done in line with the circuit you want to meassure.

now, nr 1 is bad because you run extra voltage onto a circuit already at operating voltage, or you reverse the poles etc. you stand a good chance of frying fragile components. nr 3 across two pins of a circuit is just going to be a short really.

measure the voltage against the body (ground) and then go pin to pin and see if there is any signals i.e. 5v, 12v etc. i would guess the frequency of the signal is going to be too high to pick up with a voltmeter to see the signal pattern, so you are most likely looking for a steady voltage reading, if it bounces around you got nothing.

good luck

m3guy

02-05-2008 09:39 PM

Thanks man very useful,So If I do have consistant voltage coming from the plug it's good if nothing then electrical problems it looks like,Im going to head back to the wreckin yard tommorrow and get my old air flow sensor back,

Shoes R

02-06-2008 04:10 AM

just be cheaper to get a fake one

m3guy

02-06-2008 09:09 AM

ummm

Cheaper to get a fake MAF? where and how? mega squirt I cannot afford right now- Are their ways of moding the maf?

Mickey Knox

02-06-2008 09:30 AM

well, i dont know what the signals from the maf should look like, and i dont know where you could find out which signal should be where. but if you get no signal on any pin chances are something is wrong with it. this wont be dead on, more an approximation to find out what part is actually causing the problem.

Blades

02-06-2008 09:32 AM

retard the timing and go test it again .. you will pass with flying colors. Or get some performance cams and never worry about it again :)

SeRb

02-06-2008 09:38 AM

Quote:

Originally Posted by m3guy
(Post 1107926)

Cheaper to get a fake MAF? where and how? mega squirt I cannot afford right now- Are their ways of moding the maf?

he means a fake e-test

you pay the money and u pass no matter what

Dr. Flyview

02-06-2008 12:07 PM

Quote:

Originally Posted by SeRb
(Post 1107940)

he means a fake e-test

you pay the money and u pass no matter what

Wouldn't you still want your car to run properly though?

m3guy

02-06-2008 12:59 PM

hey all

hey all friends...I have bad delema here,i went and got my old MAF back,pluged It all in reset the computer
and Im getting the same problem the idle is all over the place with the check engine light going on and off you can smell how rich it is still with a 1215 code for maf?? Im stumped the other one worked good b4 I put that shit one in now it runs the same as the old one get it? lol Any help please,is their like an inline fuse or relay?